In the use of spray booms, it is of importance to be able to mark the field being traversed by the sprayer so that there are no gaps between the sprayer runs and no overspray, which is wasteful.
In the past, markers using dyes, foam or paper to mark a field have been proposed. Others provide for a mechanical action on the field to form a line which can be followed in a subsequent passage of the sprayer. These devices tend to be complex and difficult to install and handle.
The present invention aims at the provision of a novel mechanical field marker that is simple and easy to install and use.